One for the metal workers (control arms)

Zedn · #1 (**permalink**) 08-12-2009, 02:58 AM

I have shortened my control arms and im now starting to get paranoid about welding dissimilar metals (forged steel / steel tube). For any other part of the car i wouldnt give it a second thought, but this part is extremely critical.

My plan was to maintain the original Jag shock mounts, but this meant cutting right back to the forged section of the arm.

Any one got any opinions? At this stage i am actually considering grabing another pair of arms and cutting in the middle and sleaving or dowling it. Or possibly filling in with a gusset between the shock mount and forged bracket.

Heres a pic. This was done by cutting a fillet out and welding with an arc as hot as i could get it.

Cheers.

Andrew429 · #2 (**permalink**) 08-12-2009, 06:16 AM

Hi Zedn,

I got mine as part of a kit.
They have been cut and sleeved approx. 2" in from the Y at the Diff end.
This appears to be the opposite end to your pic.
The original shock mounts are re-used with some spacers allowing me to run larger hollow driveshafts.

Cheers

Andrew

Maurice Butler · #3 (**permalink**) 08-13-2009, 02:50 AM

Hi,

have a look at http://www.erareplicas.com/427/shorten.htm details how it is done.

Don't know the answer to your welding question though

Maurice

Zedn · #4 (**permalink**) 08-13-2009, 03:07 AM

Thanks,

I have come up with a fail safe. I am going to make a reinforced angle bracket that connects the shock mount to the threaded hole for the original trailing arms. That will take some of the load and in the event of a failure, hopefully will hold it together for a short time.

The idea came to me in the shower of all places

Liam

peterp · #5 (**permalink**) 08-14-2009, 02:31 AM

Zedn,you are making this hard for yourself,contact Laurie Bongalais
peter

REPTYL · #6 (**permalink**) 08-16-2009, 12:55 AM

Had mine shortend by Laurie many years ago.
My drivers side let go after 3 years, luckly in a carpark and not the race track.
It happend about 2 months after Laurie snapped his on the run and gun at West Wyalong.
I took it back to Laurie to repair and then took it to Martin at Kenmer to have two reinforcing bars added each side to trianglate the end forces.
Haven't had a problem since.

AC-460 · #7 (**permalink**) 08-20-2009, 05:11 AM

The problem is the tubes are hollow dirt and moisture get inside make rust and slowly weaken the tubes. The tube is like a tailshaft its designed to twist to absorb shock. When you shorten the control arms you are increasing the load per inch of tube...
Welding stays in the corners will stop the tube absorbing stress the full length of the tube and probably result in the tube failing at the end of the stays were there welded on the tube. The best thing you can do is to forget welding stays in ... just fit a watts link setup to the top of your outer housing